(a) Field of the Invention
An exemplary embodiment of the present invention relates to a method of receiving a downlink signal and an adaptive communication method and an adaptive communication apparatus, in a mobile wireless backhaul network.
(b) Description of the Related Art
In a mobile wireless backhaul network for a high speed moving object that multi users gets into, the high speed moving object serves as a single terminal to transmit/receive data to/from a base station. Further, the high speed moving terminal serves data to user terminals inside the high speed moving object using technologies such as Wi-Fi and a femto cell. The method has an advantage of overcoming a propagation loss occurring while a radio wave received from an outside of the high speed moving object passes through the inside of the high speed moving object. Further, the high speed moving terminal at a cell boundary performs a group handover, and as a result a handover signaling burden on a lot of user terminals inside the high speed moving object that should each perform the handover may be reduced.
Typically, in the mobile wireless backhaul network for the high speed moving object, a line of sight (LOS) component of a signal appears to be larger than a non LOS (NLOS) component. Due to the feature, in the moving wireless backhaul network for the high speed moving object, it is difficult to obtain a rank of a channel between the base station and the high speed moving terminal, and therefore it is difficult to apply a multiple antenna (multiple input multiple output (MIMO)) technology.
Similar to the existing cellular network, in the moving wireless backhaul network for the high speed moving object, the base station becomes a reference and thus provides a synchronous signal and a pilot signal and the high speed moving terminal receives the signals to adapt to a frame boundary of the base station, thereby performing communications. Meanwhile, unlike the typical cellular network, in the moving wireless backhaul network for the high speed moving object, the high speed moving terminal on behalf of a plurality of user terminals transmits/receives data to/from the base station, and therefore the number of terminals directly transmitting/receiving data to/from each base station is very small and the number of terminals directly communicating with the base station may be one or may not be present. Therefore, continuously transmitting, by all the base stations, the synchronous signal, the pilot signal, the base station control information signal, etc., may cause power consumption.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.